Planetary Gear : A planetary gear contains a sun gear, planetary gears and a ring gear. These 3 components can be used by the automatic transmission for either the input, the output or can be held stationary. The transmission can choose which piece plays which role to determine the gear ratio for the gear set. By adding a band, you can hold the planetary gear assembly stationary to get a reverse. Clutches are used to apply each function of the gear assembly.

Most automatic transmissions use these planetary gears. When an automatic transmission has a problem, sometimes the planetary gears will fail. Different things happen when the planetary gears fail such as noises, no reverse, no overdrive, etc. Often, lack of transmission fluid pressure can cause these gears to wear out prematurely. Keeping automatic transmission fluid full inside the transmission can help prevent problems with these gears. In some cases, the manufacturer will have a defective design requiring updates to be performed so that the planetary gears will get the necessary lubrication to prevent future problems.

When a planetary gear fails, you have to rebuild the entire transmission. The transmission must come out and be totally disassembled to even get to the planets. Often times, the planetary gears are replaced as an assembly.

Bands are used as braking or holding planetary gears to slow or stop the gear set assembly. The band is placed around a drum that is either rotating or stationary. The band’s inner side is lined with friction material like a clutch uses. Each band in the transmission is held in place by an anchor and is applied with a servo. If the band breaks, you can loose a gear or multiple gears depending on the function of the desired planetary options.

Guy’s Automotive can replace or rebuild your transmission. Automatic transmissions, manual transmissions and CVT can all be assessed by our auto technicians. Call today for an appointment or estimate for your transmission needs and more.